It is located in the Augusta-Margaret River and Busselton council areas, and is claimed to have the highest visiting numbers of any national park in Western Australia.

[3] The park either passes through or contains historic sites including the Cape Leeuwin water wheel.

The Leeuwin Complex is a strongly metamorphosed igneous Proterozoic rock made up mostly of granitic and anorthositic gneisses.

The Dunsborough Fault forms the eastern boundary of the Leeuwin Complex where it adjoins the sedimentary Perth Basin.

Further inland are shrublands, woodlands, and forests, including peppermint tree (Agonis flexuosa) and Banksia shrubland and woodland, and significant stands of tall karri (Eucalyptus diversicolor) and jarrah (Eucalyptus marginata) forest.

The national park was created from crown lands along the Leeuwin-Naturaliste Ridge at a time after the main primary industries in the region had been dairying and forestry, and when increased land-use conflict was arising from the spread of wineries, increased population on hobby farms and other agricultural activities.

On 8 December 2021, a bush fire began near Mammoth Cave within Leeuwin-Naturaliste National Park,[8] said to have been deliberately lit.

WA premier Mark McGowan urged people to leave the area as soon as possible due to high fuel loads and dangerous conditions.